Conventionally, a vehicle information rewriting system is known. The vehicle information rewriting system prevents memory contents about vehicle information including software in an electronic control unit for a vehicle from being rewritten by unauthorized use of a program rewriting tool by anyone except for a person entitled to use the program rewriting tool (for example, see Patent Document 1). The vehicle information rewriting system disclosed in Patent Document 1 is configured to include a wireless polling unit in the rewriting tool. The wireless polling unit detects a wireless authentication medium that the person entitled to use the program rewriting tool possesses, by which the rewriting tool can authenticate the wireless authentication medium. [Patent Document 1] Japanese Patent Application Laid-Open Publication No. 2008-59450